ProgramNode(0...10)(
  [],
  StatementsNode(0...10)(
    [InterpolatedStringNode(0...10)(
       (0...1),
       [EmbeddedStatementsNode(1...7)(
          (1...3),
          StatementsNode(3...6)(
            [StringNode(3...6)((3...4), (4...5), (5...6), "a")]
          ),
          (6...7)
        ),
        StringNode(7...9)(nil, (7...9), nil, " b")],
       (9...10)
     )]
  )
)
